Electronic networks have gained widespread acceptance today, and more and more services are being offered on these networks. Some networks are structured in wired fashion; others are constituted wirelessly.
With the networks coming into general use, there has been a need for improving the reliability of communication over any of the networks being used. For example, if some fault occurs on a network path over which target data is being transmitted, other paths are arranged to be formed so that the same data may be transmitted over the alternative paths to its destination in order to prevent data dropouts (as described illustratively in Japanese Published Unexamined Patent Application No. Hei 11-98161).
In recent years, wireless LANs (local area networks) have become popular as household networks because this type of network is easier to install than its wired counterpart. However, because of its particular characteristics, the wireless LAN tends to be less reliable than the wired LAN.
For example, a wireless LAN setup obviously involves sending and receiving data wirelessly. The status of communication in that setup can easily deteriorate if a person crosses a data path between a transmitter and a receiver in communication or if humidity or other ambient factors in the household change significantly. The worsening state of communication can result in data dropouts or other irregularities during transmission or reception (i.e., communication).
Methods have been proposed and implemented for compensating video data that went missing for some reason during transmission or reception. For example, if data encoded using the MPEG (Moving Picture Experts Group) standard is to be decoded and if any video stream to be decoded has a missing packet, reproduction of that video stream is continued by supplementing it with the frame preceding that of the missing packet or some of the blocks in the preceding frame.
Such error-disguising methods may be adopted by the decoder that processes video streams. This makes it possible to prevent inconvenience such as discontinuation of video presented to the user.
On the other hand, errors caused by missing audio (data) packets cannot be disguised effectively by the same measures as those for addressing video data. Few effective methods have been proposed to compensate for missing audio packets. As a result, users are often left with unresolved irregularities stemming from missing audio data such as audio disconnections.